1. Field of the Invention
The present invention relates to a method of writing data in a data storage system and an apparatus therefor, and more particularly, to a method by which a dummy write is executed before executing a write mode, wherein a write head pole tip is fully thermally expanded to reduce bit error rate occurring early in the write mode, and an apparatus therefor.
2. Description of the Related Art
In general, a hard disk drive, which is one of a number of auxiliary memories of a computer, reproduces data written on the hard disk drive using a magnetic head or writes new data on the hard disk drive to contribute to a computer system. As storage capacity and storage density increase, and a physical size of the hard disk drive decreases, linear density, bits per inch (BPI), and the track density, tracks per inch (TPI), of the hard disk drive increase. Thus, a method of more precisely and quickly controlling a position of a head of the disk drive and a delicate mechanism are required.
However, the tip of a pole on the head of the hard disk drive thermally expands depending on the ambient temperature. Thus, the pole tip is shrunk in the earlier writing, but thermally expands until saturation after the pole tip receives a write current for a predetermined time.
A waveform of a typical write current is shown in FIG. 1. In FIG. 1, the pole tip PT is shown attached to an air bearing surface ABS and disposed adjacent a recording medium (DISK). The ABS and pole tip are illustrated adjacent a time line of a write current waveform. During a period of time between t0 and t1, the pole tip PT is shrunk to a size A because a temperature of the pole tip approaches an ambient temperature of the pole tip before writing begins. When the write current is supplied to the head due to a write command at the time t1, the pole tip PT initially remains in the shrunken state of the size A, and if the write current is supplied for a predetermined time (t2-t1), the temperature of the pole tip increases and the pole tip thermally expands until saturation at a size B.
As a result, a flying height of the head from a disk surface changes and thus the flying height gradually decreases in the earlier writing until the pole tip thermally fully expands. Thus, where a signal written in an early stage of a write current application is reproduced, the level of the signal is attenuated, and as a result, errors occur where data written in an initial sector is reproduced. In particular, the probability that errors will occur in the initial sector is higher if the ambient temperature is low.